package TCPEcho;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TCPEchoSever {
    private ServerSocket serverSocket = null;
    //创建服务器需要手动指定端口号
    public TCPEchoSever(int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }

    public void start() throws IOException {
        System.out.println("服务器启动！");
        while(true){
            ExecutorService pool = Executors.newCachedThreadPool();
            //TCP是有连接的
            //需要accept方法来接听电话，然后才能进行通信
            Socket clineSocket = serverSocket.accept();
            pool.submit(()->{
                try {
                    processConnetion(clineSocket);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            });
        }
    }

    public void processConnetion(Socket clineSocket) throws IOException {
        System.out.printf("[%s:%d],客户端上线\n" ,clineSocket.getInetAddress(),clineSocket.getPort());
        //循环获取客户端请求并返回响应
        try (InputStream inputStream = clineSocket.getInputStream();
             OutputStream outputStream = clineSocket.getOutputStream()){
            Scanner scanner = new Scanner(inputStream);
            PrintWriter writer = new PrintWriter(outputStream);
            while(true){
                if(!scanner.hasNext()){
                    System.out.printf("[%s:%d],客户端下线！\n",clineSocket.getInetAddress(),clineSocket.getPort());
                    break;
                }
                //1、获取请求并解析，这里注意隐藏的约定，next读的时候要读到空白符才会结束
                //因此客户端发来的请求必须要以空白符结尾
                String request = scanner.next();
                //2、根据请求计算响应
                String response = process(request);
                //3、把响应返回给客户端
                writer.println(response);
                //清空缓冲区
                writer.flush();
                System.out.printf("[%s:%d],req:%s,resp:%s",clineSocket.getInetAddress(),clineSocket.getPort(),request,response);
            }
        }finally {
            clineSocket.close();
        }
    }

    public String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        TCPEchoSever tcpEchoSever = new TCPEchoSever(7675);
        tcpEchoSever.start();
    }
}
